Memory cards with built-in memory chips are commonly used as recording media and for storing information. They are highly portable, and are thus commonly employed as recording media in mobile electronic devices such as personal digital terminals and mobile phones. These mobile electronic devices, as they become smaller and thinner, will require further downsizing of memory cards to afford better portability.
On the other hand, smaller memory cards carry an increased risk of accidental ingestion, typically by children. Accordingly, technology to prevent the accidental ingestion of memory cards has been proposed. (For example, refer to Patent Document 1).
In the memory card disclosed in Patent Document 1, an emetic agent is first mixed with a resin material that is then used for making the memory card casing by insert-molding so as to form a casing containing the emetic agent. In this way, the emetic agent contained in the casing surface comes into contact with the tongue if the memory card is placed in the mouth, and results in immediate spitting-out of the memory card. Patent Document 1 further discloses mixing of an emetic agent in the ink used for printing on the surface of a memory card to prevent its accidental ingestion.
In Patent Document 1, the emetic agent is exposed on the casing surface or ink surface of the memory card, and may thus attach to the fingertip of the user when the user handles the memory card, resulting in removal of the emetic agent from the surface of the memory card. As a result, if a child puts the memory card in his/her mouth, it will take some time for the emetic agent contained inside the casing or ink to leak out to the mouth. Accordingly, accidental ingestion of memory card cannot be reliably prevented.
Still more, insert-molding is conducted under conditions in which the emetic agent is contained in the resin material in the memory card disclosed in Patent Document 1. The quality of the emetic agent may thus be altered or degraded as a result of heat being applied while molding the casing. This may result in loss of the emetic effect generated if the memory card is placed in the mouth. In addition, resin material or ink containing the emetic agent needs to be prepared separately, complicating the process of manufacturing the memory card.
[Patent Document 1] Japanese Patent Unexamined Application No. 2006-3955.